Expression levels of Bax, Bcl-2 and brain-derived neurotrophic factor in the rat brain motor cortex after over fatigue-induced sudden death

Yang Ren-jun; Yin Wei-yao; Li Hua

doi:10.3969/j.issn.2095-4344.2016.49.012

Abstract：BACKGROUND:Exercise-induced sudden death is a common phenomenon during exercising, but the mechanism is not ful y understood. <br> OBJECTIVE:To investigate the morphological changes of motor cortex and the expression levels of Bax, Bcl-2 and brain-derived neurotrophic factor (BDNF), and to explore the occurrence and regulatory mechanism of exercise-induced sudden death during the training of continuously exhaustive loaded-swimming. <br> METHODS:Seven selected from 130 male Sprague-Dawley rats were randomly as blank control group and the remaining rats were modeled into over fatigue, fol owed by continuously exhaustive loaded-swimming with the training cycle of 36 hours. Then seven rats were kil ed as groups 1, 2 and 3 at 6, 9, 12 and 36 hours of exhaustive loaded-swimming and al dead rats in near several experiments in the same model without choking water in each training or within 24 hours after the 6th 36 hours of training as exercise-induced sudden death group (n=5). The morphological changes of motor cortex were observed by hematoxylin-eosin staining, and the expression levels of Bax and Bcl-2 proteins and BDNF were examined by immunohistochemistry. <br> RESULTS AND CONCLUSION:(1) Compared with the blank control group, the morphology of motro cortex changed significantly, and the expression levels of Bax and Bcl-2 proteins and BDNF in the groups 1, 2, and 3 and exercise-induced sudden death group were significantly up-regulated (P<0.05). (2) Moreover, in the groups 1, 2, and 3 and exercise-induced sudden death group, the expression levels of Bax and Bcl-2 proteins showed an increasing trend, especial y Bcl-2;while, the expression level of BDNF increased firstly and then decreased. (3) In conclusion, the enhanced expression levels of Bax and Bcl-2 proteins and BDNF in brain motor cortex of fatigue and exercise-induced sudden death groups maybe related to the protection-inhibition mechanism. The reduced expression of BDNF in brain motor cortex may be one of the reasons inducing sudden death during over fatigue.